Types of Views 99
spectively, have different ratios of foreshortening (and are therefore drawn at different scales) when pro-
jected to the plane of projection. The wide angle choice gives the designer considerable flexibility and
control of the pictorial view.
In trimetric projections, the direction of viewing is such that all of the three axes of space appear un-
equally foreshortened. The scale along each of the three axes and the angles among them are deter-
mined separately as dictated by the angle of viewing. Approximations in trimetric drawings are common.
Limitations of Axonometric Projection.
Objects drawn with axonometric projection do not appear larger or smaller as they extend closer to or
further away from the viewer. While advantageous for architectural drawings and sprite-based video
games, this results in a perceived distortion, as, unlike perspective projection, it is not how our eyes or
photography usually work. An additional problem in the case of isometric projection is that there are
times when it becomes difficult to determine which face of the object is being observed. In the absence
of proper shading, and with objects that are relatively perpendicular and similarly proportioned, it can be-
come difficult to determine which is the top, bottom, or side of the object, since each face is given simi-
lar dimensions.
5.7 PICTORIAL DRAWINGS
Pictorial drawings are not often used for construction purposes. However, on some working drawings
pictorial views are used to reveal information that orthographic views alone would be incapable of show-
ing; other situations may require a pictorial drawing essentially to supplement a major view. Pictorial pro-
jection, unlike multiview projection, is designed to allow the viewer to see all three primary dimensions
of the object in the projection. Pictorial architectural drawings and renderings are very easy to under-
stand and are therefore used extensively to depict a three-dimensional view of an object and for explain-
ing project designs to laypersons for sales-presentation purposes. They enable an inexperienced per-
son to interpret drawings and quickly visualize the shape of individual parts or various components in
complicated mechanisms. To convey as much information as possible, the view is oriented to show the
sides with the most features. In many cases, orthographic (multiview) drawings provide information in a
format that makes it difficult for laypersons to visualize the total project.
Orthographic/multiview drawings are typically dimensioned and are usually drawn to a specific scale
(Figure 5.23). Although pictorial drawings may be dimensioned and drawn to scale, their main purpose
is to give a three-dimensional representation of the building or object. As illustrators often take artistic
liberties with scale and proportion, the reader should only use pictorial drawings for general reference.
And although they are not usually dimensioned and exact scaling is not required, proportions are nev-
ertheless expected to be maintained. When pictorial drawings are dimensioned and contain other spec-
ifications that are needed to produce the part or construct the object, they are considered to be working
drawings.
Whereas a multiview drawing is designed to focus on only two of the three dimensions of the object,
a pictorial drawing provides an overall view. The tradeoff is that a multiview drawing generally allows a
less distorted view of the features in the two dimensions displayed while lacking a holistic view of the ob-
ject (thus needing multiple views to fully describe the object).